Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
REVENUES	$ 442,845	$ 474,935	$ 1,324,922	$ 1,385,651
EXPENSES:
Operating	316,865	326,349	940,065	956,713
General and administrative	28,303	27,699	79,546	81,543
Depreciation and amortization	36,507	42,924	109,564	127,328
Restructuring charges		4,010		4,010
Asset impairments	355		614
Costs and Expenses, Total	382,030	400,982	1,129,789	1,169,594
OPERATING INCOME	60,815	73,953	195,133	216,057
OTHER (INCOME) EXPENSE:
Interest expense, net	17,029	16,937	50,141	51,277
Other (income) expense	(65)	54	(108)	103
Total non-operating expense (income)	16,964	16,991	50,033	51,380
INCOME BEFORE INCOME TAXES	43,851	56,962	145,100	164,677
Income tax expense	(2,673)	(1,622)	(8,400)	(5,447)
NET INCOME	$ 41,178	$ 55,340	$ 136,700	$ 159,230
BASIC EARNINGS PER SHARE	$ 0.35	$ 0.47	$ 1.16	$ 1.36
DILUTED EARNINGS PER SHARE	0.35	0.47	1.15	1.35
DIVIDENDS DECLARED PER SHARE	$ 0.42	$ 0.54	$ 1.26	$ 1.62